Rotrou III (bef. 1080 – 8 May 1144), called the Great (le Grand), was the Count of Perche and Mortagne from 1099. He was the son of Geoffrey II, Count of Perche, and Beatrix de Ramerupt, daughter of Hilduin IV, Count of Montdidier. He was a notable Crusader and a participant in the Reconquista in eastern Spain, even ruling the city of Tudela in Navarre from 1123 to 1131. He is commonly credited with introducing Arabian horses to the Perche, giving rise to the Percheron breed. By his creation of a monastery at La Trappe in memory of his wife, Matilda, daughter of Henry I of England, in 1122 he also laid the foundations of the later Trappists. First Crusade Rotrou took part in the First Crusade, travelling with the army of the duke of Normandy, Robert Curthose. What influenced Rotrou in this regard were probably familial connexions. He was related to the Anglo-Norman aristocracy and the Perche was a march (border region) in southern Normandy. A sister was married to Raymond I of Turenne, who was a fellow Crusader in the following of Raymond IV of Toulouse. His mother, Beatrix, was a sister of Ebles II of Roucy, who had campaigned in Spain in 1073, and Felicia, who married Sancho Ramírez, King of Aragon. A religious motivation cannot be discounted. According to the Chanson d'Antioche, Rotrou was under the command of Bohemond of Taranto during the Siege of Antioch, and was one of the first to go over the city's walls through scaling ladders on 3 June 1098. When the Crusaders had to confront a Seljuk relief force two weeks later in open battle, Rotrou was one of the front line commanders. He fulfilled his vow and made it all the way to Jerusalem. The Chanson also mentions his bravery at the siege of Nicaea of 1097. In 1107, Rotrou built a castle on land held partly allodially and partly in lordship by Hugh II of Le Puiset, thus challenging Hugh's rights to the estate. Since Pope Urban II had taken Crusaders' "houses, families, and all their goods into the protection of Saint Peter and the Roman church", and both Hugh and Rotrou were veterans of the First Crusade, the dispute was intractable. Bishop and lawyer Ivo of Chartres could not resolve it, since it involved a judicial duel, over which the church was not allowed to preside, and